In case you still are unsure, here is detailed explanation.
First, go to the thread you wish to create a poll on (it must be your own thread.)
On the top right part of your first post click *edit. On the page it directs you to, scroll to the bottom, you will see 3 tabs; options, upload attachments, and poll creation.
You should be able to figure it out from there.
Beware of Jess the Mini-Mod. He's still here...